Your checking account has two separate identification numbers

A checking account uses two different numbers to move money: your account number and your bank's routing number. The account number identifies your specific account at your bank. The routing number identifies the bank itself. Together, they tell the payment system exactly where your money is and where it needs to go.

You will see both numbers printed on the bottom left of every check you write. The routing number comes first (nine digits), then your account number (typically 10 to 12 digits, though this varies by bank). When you set up direct deposit, pay a bill online, or send money to someone else's account, you are giving the payment system these two pieces of information so it can find your bank and then find you within that bank.

Some banks also assign you a customer ID or account holder number, but this is different from your account number. The customer ID identifies you as a person at that bank and stays the same even if you open multiple accounts. Your account number changes if you close the account and open a new one.

Key Takeaways

  • Your checking account has an account number (10 to 12 digits) and your bank has a routing number (9 digits), and you need both to send or receive money.
  • The routing number appears first on the bottom of your checks, followed by your account number.
  • Your bank may also assign you a customer ID, which identifies you as an account holder rather than identifying a specific account.
  • Different banks use different account number lengths, so do not assume yours matches someone else's account at the same bank.

Where to find your account number

Your account number is printed on the bottom left of every check, after the routing number. If you do not have checks, log into your online banking portal — your account number appears on the account summary or account details page. You can also call your bank's customer service line and they will read it to you over the phone.

Some banks print your account number on your debit card, usually on the front or back. Others do not. If your bank does not print it on the card, you will need to use one of the other methods above.

Where to find your routing number

Your routing number is also on the bottom of your checks, as the first set of nine digits on the left side. If you do not have checks, you can find it on your bank's website — most banks list it in the "wire transfer information" or "account information" section. You can also call customer service, or search online for "[Your Bank Name] routing number" along with your state, since some large banks have different routing numbers for different regions.

The routing number is the same for all customers at your bank (or at a specific branch, depending on the bank's structure). It does not change when you open a new account or close an old one.

Why banks use two numbers instead of one

The payment system needs to know two things: which bank to send money to, and which account at that bank to send it to. One number cannot do both jobs efficiently. The routing number is like an address for the bank building. The account number is like your apartment number inside that building. Together, they create a complete destination.

This two-number system also makes it easier for banks to manage accounts. A bank might have millions of customers, but only one routing number. If the bank merged with another bank or changed its name, the routing number might change, but your account number would stay the same. This separation keeps the system flexible.

What happens if you give the wrong number

If you give someone the wrong account number but the correct routing number, the payment will go to the wrong account at your bank — possibly to another customer's account. If you give the wrong routing number but the correct account number, the payment will go to the wrong bank entirely. Either way, the money does not reach you.

Most banks have fraud protections and can reverse a payment that lands in the wrong account, but this takes time — usually several business days. The safer approach is to double-check both numbers before you give them out. Copy them directly from your checks or your online banking portal rather than typing them from memory.

Account numbers and routing numbers for wire transfers

Wire transfers require both your account number and your routing number, just like other transfers. However, some banks ask for additional information during a wire transfer: your full name, your address, and sometimes a reference number or description of what the money is for. Wire transfers are faster than ACH transfers (which typically take one to three business days), but they are also harder to reverse if something goes wrong.

When you initiate a wire transfer, your bank will ask you to confirm all the details before processing it. Take time to verify the account number and routing number one more time at this stage, because once the wire leaves your bank, recovery is difficult.

International transfers and SWIFT codes

If you are sending money to someone outside the United States, you will need a different identifier instead of a routing number. International transfers use a SWIFT code (also called a BIC code) to identify the foreign bank, and an IBAN (International Bank Account Number) instead of a domestic account number. The IBAN is longer than a domestic account number — typically 15 to 34 characters — and includes the country code and bank information in one string.

Your U.S. bank can tell you its SWIFT code, and you can ask the person receiving the money for their IBAN. Some banks charge a fee for outgoing international transfers, and the receiving bank may charge a fee as well. The exchange rate and fees can significantly reduce the amount that arrives, so ask your bank for the total cost before you send.

Frequently Asked Questions

Can someone steal money from my account if they know my account number and routing number?

They would need additional information to set up a transfer or direct debit. However, it is still wise to keep both numbers private. Share them only with people you trust or with established companies you are paying. If you suspect fraud, contact your bank when ready.

Do all checking accounts at the same bank have the same routing number?

Usually yes, but not always. Large banks sometimes use different routing numbers for different regions or branches. Check your specific bank's website or call customer service to confirm the routing number for your location.

What is the difference between my account number and my customer ID?

Your account number identifies a specific checking account. Your customer ID identifies you as a person at the bank. If you open a savings account at the same bank, it has a different account number but the same customer ID. You need the account number to send or receive money.

If I close my checking account and open a new one, do I get a new account number?

Yes. Each account has its own unique account number. Your customer ID may stay the same, but the account number changes. This is why you need to update your direct deposit and automatic payments when you switch accounts.

Can I find my account number on my debit card?

Some banks print it there, but many do not. The debit card number is different from your account number. If your bank does not print the account number on your card, check your checks, your online banking portal, or call customer service.